Statins may not prevent blood clots

London: Cholesterol-lowering drugs, statins, are unlikely to prevent blood clots (venous thrombo-embolism) in adults, according to a large analysis by international researchers.In 2009, an additional analysis of data from a randomized controlled trial called the JUPITER trial reported that the statin rosuvastatin halved the risk of venous thromboembolic events among apparently healthy adults.

However, this finding was based on a small number of patients who had thromboembolic events (34 vs 60). To gather more evidence about the possible benefits of statins, a group of international researchers led by Kazem Rahimi from the George Centre for Healthcare Innovation at the University of Oxford in the UK, combined the results (performed a meta-analysis) of 29 suitable published and unpublished randomised controlled trials of the effects of statins involving over 100 000 participants and more than 1000 events: Only two studies presented venous thrombotic events in the published report, but such events had been recorded as adverse events in all of the included trials, which the researchers were able to include in their analysis.

In the combined analysis, the researchers found that venous thrombosis occurred in 0.9 percent of people taking statins compared to 19 percent of people not taking statins, which suggests that statins have a very small, if any, effect.

These results did not change when the researchers excluded the findings of the JUPITER trial. They also found that there was no effect at all in people taking high doses and low doses of statins.

"This study provides a more detailed assessment of the potential effects of statins (or higher dose statins) on venous thromboembolic events than has previously been possible. We were unable to confirm the large proportional reduction in risk suggested by some previous studies," the researchers concluded.

"However, a more modest but perhaps clinically worthwhile reduction in venous thromboembolic events in some or all types of patient cannot be ruled out," they added. The findings were published in this week's PLOS Medicine.